Mann is the director of the Earth System Science Center at Penn State. He suggests that new data indicates that our models of climate change are incorrect and have been underestimating the rate at which the Greenland and Antarctic Ice sheets are melting.

These ice sheets add water directly to the oceans, raising sea level worldwide. Data indicates that this melt is happening quicker than climate models had predicted, Mann said.

He told The Guardian: "The models have typically predicted that will not happen for decades but the measurements that are coming in tell us it is already happening so once again we are decades ahead of schedule."

Sea ice itself doesn't add to sea levels because it is already floating in the water and taking up space, similar to melting ice in a glass of water doesn't raise the liquid level — try it at home if you don't believe me — but methane gas trapped in air bubbles in the ice could accelerate climate change. Previous climate models hadn't taken this into account, Mann said, and we don't know how much methane and other greenhouse gasses could be contained in the ice.

Mann hypothesizes that these sea level increases could spell disaster for several low-lying islands. He predicts that many will need to evacuate within the decade. In fact, some countries are already experiencing enough trouble from rising water that they are planning evacuation.

The tiny island country of Tuvalu, halfway between Hawaii and Australia, is already experiencing lowland flooding that is contaminating their drinking water and decreasing food production, and erosion from the rising water is eating away their land.

They have already asked Australia and New Zealand to accept its 11,000 citizens, but neither country has agreed to do so.

Other islands that Mann said could be imminent danger include the Pacific Islands, which at their tallest are only 4.6 meters above sea level, and Kivalina Island in Alaska.